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oe1(光电查) - 科学论文

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出版时间
  • 2015
研究主题
  • Calibration process of OSL detectors
  • Iodine-131
  • OSL-BeO
  • Dosimetry of staff and patients
  • Optically Stimulated Luminescence (OSL)
应用领域
机构单位
  • Akdeniz University
316 条数据
?? 中文（中国） ▾

  • Development of a photochemical source for the production and calibration of acyl peroxynitrate compounds

    摘要： A dynamic system for the calibration of acyl peroxynitrate compounds (APNs) has been developed in the laboratory to reduce the difficulty, required time, and instability of laboratory-produced standards for difficult-to-synthesize APN species. In this work we present a photochemical source for the generation of APN standards: acetyl peroxynitrate (PAN), propionyl peroxynitrate (PPN), acryloyl peroxynitrate (APAN), methacryloyl peroxynitrate (MPAN), and crotonyl peroxynitrate (CPAN). APNs are generated via photolysis of a mixture of acyl chloride (RC(O)Cl) and ketone (RC(=O)R) precursor compounds in the presence of O2 and NO2. Subsequent separation by a prep-scale gas chromatograph and detection with a total NOy instrument serve to quantify the output of the APN source. Validation of the APN products was performed using iodide ion chemical ionization mass spectroscopy (I? CIMS). This method of standard production is an efficient and accurate technique for the calibration of instrumentation used to measure PAN, PPN, APAN, MPAN, and CPAN.

    关键词： PPN,calibration,PAN,APAN,acyl peroxynitrate compounds,photochemical source,CPAN,MPAN

    更新于2025-09-09 09:28:46

  • 3-D measurement of 2-D jet by 3-D 3-C SPIV

    摘要： The stereo PIV, commonly known as the SPIV, is capable of measuring all the three velocity components in a two-dimensional measurement plane and thus classi?ed as 2-D 3-C PIV. Even though the SPIV utilizes a set of two cameras, the positions of the measurement points are assumed to be located in the central plane of the illuminated volume, which is usually the zone of laser light sheet. This assumption makes the SPIV versatile and its calibration procedure very handy. But, if the three-dimensional orientation of the cameras can be calibrated precisely, the three-dimensional position of the particles that may be distributed in the depth of the illuminated zone can be calculated. The authors of this study have proposed a new algorithm that enables the fully three-dimensional measurement by SPIV and it can be classi?ed as 3-D 3-C SPIV. Presently, the three-dimensional turbulent measurement of a plane jet has been carried out with the use of presently proposed 3-D 3-C SPIV and the transverse distributions of the turbulence statistics have been obtained in the depth direction of 3-D 3-C SPIV. The results are compared with those by standard PIV, i.e., 2-D 2-C PIV, and thus, the accuracy and the applicability of 3-D 3-C SPIV have been evaluated.

    关键词： 2-D jet,Stereo PIV,Turbulence statistics,3-D measurement,Camera calibration,Scheimp?u¨g condition

    更新于2025-09-09 09:28:46

  • ISMAR: an airborne submillimetre radiometer

    摘要： The International Submillimetre Airborne Radiometer (ISMAR) has been developed as an airborne demonstrator for the Ice Cloud Imager (ICI) that will be launched on board the next generation of European polar-orbiting weather satellites in the 2020s. It currently has 15 channels at frequencies between 118 and 664 GHz which are sensitive to scattering by cloud ice, and additional channels at 874 GHz are being developed. This paper presents an overview of ISMAR and describes the algorithms used for calibration. The main sources of bias in the measurements are evaluated, as well as the radiometric sensitivity in different measurement scenarios. It is shown that for downward views from high altitude, representative of a satellite viewing geometry, the bias in most channels is less than ±1 K and the NE(cid:49)T is less than 2 K, with many channels having an NE(cid:49)T less than 1 K. In-?ight calibration accuracy is also evaluated by comparison of high-altitude zenith views with radiative-transfer simulations.

    关键词： ISMAR,radiometric sensitivity,Ice Cloud Imager,submillimetre radiometer,calibration,airborne demonstrator

    更新于2025-09-09 09:28:46

  • AIP Conference Proceedings [Author(s) GREEN DESIGN AND MANUFACTURE: ADVANCED AND EMERGING APPLICATIONS: Proceedings of the 4th International Conference on Green Design and Manufacture 2018 - Ho Chi Minh, Vietnam (29–30 April 2018)] - Quantification of acidity and total soluble solids in guavas by near infrared hyperspectral imaging

    摘要： In order to provide premium quality for marketing of guavas the titratable acidity (TA) and total soluble solids (TSS) levels should be determined. A reflectance near infrared hyperspectral imaging (NIR-HSI) unit in the wavelength range of 936-1696 nm, which is a nondestructive technique, was tested for use in predicting TA and TSS. Samples of 100 guavas were scanned by NIR-HIS as a group for calibration (N=67) and as a group for prediction (N=33). The average spectra from the region of interest ( ROI) of samples were used to establish the calibration models for TA and TSS by using partial least squares regression ( PLSR) to establish calibration models. The calibration model for TA gave a coefficient of determination (R2) of 0.972 and the root mean square error of prediction (RMSEP) of 0.010% and for TSS the R2 was 0.801 and the RMSEP was 0.437oBx. The accuracies of these results indicate that NIR-HSI has potential for use in measuring TA and TSS of guavas.

    关键词： calibration,prediction,model,nondestructive,near infrared

    更新于2025-09-09 09:28:46

  • Free-Space Materials Characterization by Reflection and Transmission Measurements using Frequency-by-Frequency and Multi-Frequency Algorithms

    摘要： The knowledge of the electromagnetic constitutive properties of materials is crucial in many applications. Free-space methods are widely used for this purpose, despite their inherent practical difficulties. This paper describes an affordable free-space experimental setup for the characterization of flat samples in 1–6 GHz in a non-anechoic environment. The extracted properties are obtained from the calibrated Scattering Parameters, using a frequency-by-frequency solution or a multi-frequency reconstruction. For the first, we describe how the Time-Domain Gating can be implemented and used for filtering the signals. For the latter, a weighting factor is introduced to balance the reflection and transmission data, allowing one to have a more favorable configuration. The different role of transmission and reflection measurements on the achievable results is analyzed with regard to experimental uncertainties and different noise scenarios. Results from the two strategies are analyzed and compared. Good agreement between simulation, measurement and literature is obtained. According to the reported results for dielectric materials, there is no need of filtering the data by a Time-Domain Gating in case of the multi-frequency approach. Experimental results for Polymethylmethacrylate (PMMA) and Polytetrafluorethylene (PTFE) samples validate both the setup and the processing.

    关键词： free-space method,permeability,conductivity,non-destructive testing,extraction algorithms,permittivity,time-domain gating,free-space calibration,scattering parameters,material characterization

    更新于2025-09-09 09:28:46

  • [IEEE 2018 14th International Conference on Advanced Trends in Radioelecrtronics, Telecommunications and Computer Engineering (TCSET) - Lviv-Slavske (2018.2.20-2018.2.24)] 2018 14th International Conference on Advanced Trends in Radioelecrtronics, Telecommunications and Computer Engineering (TCSET) - Formation of the image of investigated biological objects with small contrast in a scanning TV microscope

    摘要： It is analyzed ways and methods of contrast improvements of biological objects images, which are created by television optical microscope. Advantages of TV scanning microscope usage for biological objects images formations are reviewed. Methods of research stages which allow to improve microscope parameters are shown in this paper.

    关键词： image contrast,biological object,microscope calibration,microscope sensitivity

    更新于2025-09-09 09:28:46

  • Model-Based Coarse-Fine Virtual Calibration and Visual Servo for Augmented Reality-Assisted Peg-in-Hole Microassembly

    摘要： A three-dimensional (3D)-virtual calibration and visual servo are implemented for augmented reality (AR)-assisted peg-in-hole microassembly operations. By employing 3D model and ray casting, the 3D coordinates on virtual mating rod correspondent to the two-dimensional (2D) virtual image points are extracted. The detecting and tracking of image feature points for calibration is carried out by the proposed algorithm of regional template matching (TM) and scanning with edge ?tting (RTM-SEF). For achieving sub-pixel error between the feature points in real and virtual images, a coarse-?ne virtual calibration method is proposed. In regard to the image viewed by the real and virtual cameras, a calibrated virtual camera is utilized to track the mating rod. A visual servo control law including coarse and ?ne tuning is proposed to ensure sub-pixel error between the most important feature point in the real and virtual images. The AR technology is mainly employed in the alignment between micropeg and mating hole for inserting a micropeg of diameter 80 lm with length 1–1.4 mm into a mating rod with 100 lm hole.

    关键词： microassembly,visual servo,augmented reality,peg-in-hole,3D-virtual calibration

    更新于2025-09-09 09:28:46

  • Urban Land Use/Land Cover Discrimination Using Image-Based Reflectance Calibration Methods for Hyperspectral Data

    摘要： Irrespective of substantial research in land use/land cover (LULC) monitoring of urban area, hyperspectral data is not yet exploited effectively because of lack of local spectral resources and a practical reflectance calibration method. The objective of this research is to develop an effective methodology for urban LULC classification using image-based reflectance calibration methods: especially Vegetation-Impervious-Soil classes (VIS), using hyperspectral data. We used EO-1 Hyperion image of Pune City, India and assessed the suitability of different land covers as reflectance calibration surfaces. Furthermore, we performed LULC classification using different reflectance calibration methods such as Internal Area Relative Reflectance, Flat Field Relative Reflectance, and 6S for comparative analysis. Urban VIS signatures extracted from Hyperion image show distinct spectral curves at broader level. Flat Field Relative Reflectance method provides above 90 percent average overall accuracy. An advanced physics-based method such as 6S does not provide any added advantage over image-based calibration methods.

    关键词： urban LULC classification,hyperspectral data,Vegetation-Impervious-Soil classes,EO-1 Hyperion,reflectance calibration

    更新于2025-09-09 09:28:46

  • Extrinsic Camera Calibration of Display-Camera System with Cornea Reflections

    摘要： In this paper, we propose a novel method to extrinsically calibrate a camera to a 3D reference object that is not directly visible from the camera. We use a human cornea as a spherical mirror and calibrate the extrinsic parameters from the re?ections of the reference points. The main contribution of this paper is to present a cornea-re?ection-based calibration algorithm with a simple con?guration: ?ve reference points on a single plane and one mirror pose. In this paper, we derive a linear equation and obtain a closed-form solution of extrinsic calibration by introducing two ideas. The ?rst is to model the cornea as a virtual sphere, which enables us to estimate the center of the cornea sphere from its projection. The second is to use basis vectors to represent the position of the reference points, which enables us to deal with 3D information of reference points compactly. We demonstrate the performance of the proposed method with qualitative and quantitative evaluations using synthesized and real data.

    关键词： spherical mirror,cornea re?ection,camera calibration

    更新于2025-09-09 09:28:46

  • Calibration of a water vapour Raman lidar with a kite-based humidity sensor

    摘要： We present a calibration method for a water vapour Raman lidar using a meteorological probe lifted by a kite, ?own steadily above the lidar site, within the framework of the Hydrological Cycle in the Mediterranean Experiment (HyMeX) and Chemistry-Aerosol Mediterranean Experiment (ChArMEx) campaigns. The experiment was carried out in Menorca (Spain) during June 2013, using the mobile water vapour and aerosol lidar WALI. Calibration using a kite demonstrated a much better degree of co-location with the lidar system than that which could be achieved with radiosondes, and it allowed us to determine the overlap function and calibration factor simultaneously. The range-dependent water vapour lidar calibration was thus determined with an uncertainty of 2 % in the 90–8000 m altitude range. Lidar water vapour measurements are further compared with radiosondes, showing very good agreement in the lower troposphere (1–5 km) and a relative difference and standard deviation of 5 and 9 % respectively. Moreover, a reasonable agreement with MODIS-integrated water vapour content is found, with a relative mean and standard deviation of 3 and 16 % respectively. However, a discrepancy is found with AERONET retrievals, showing the latter to be underestimated by 28 %. Reanalyses by the ECMWF/IFS numerical weather prediction model also agree with the temporal evolution highlighted with the lidar, with no measurable drift in integrated water vapour content over the period.

    关键词： kite,HyMeX,MODIS,AERONET,calibration,ECMWF/IFS,Raman lidar,ChArMEx,water vapour,WALI

    更新于2025-09-09 09:28:46